# Accelerated early weight gain of neonatal puppies from overweight bitches compared to lean dams in spite of similar milk macronutrient composition

## TL;DR

Puppies from overweight dogs gain more weight early in life compared to those from lean dogs, even though milk composition is similar.

## Contribution

First study to compare neonatal puppy growth and milk composition in overweight versus lean dams.

## Key findings

- Puppies from overweight dams had higher average daily weight gain in the first few days of life.
- Milk macronutrient composition was similar between lean and overweight dams during lactation.
- Swimmer puppy syndrome was observed more frequently in puppies from overweight dams.

## Abstract

Lactation is the final pathway for the maternal metabolism to influence the neonate. Studies in women and animals have shown maternal body condition affecting milk composition and/or offspring growth and adiposity. The effect of the body condition of the dam on neonatal puppy growth rate has never been examined, despite a growing population of overweight breeding dogs. This study aimed to compare the milk macronutrient composition and puppy growth rate during the neonatal period between overweight and lean bitches.

A total of 16 litters from 15 medium- to large-breed client-owned dogs were enrolled after whelping. Dams were classified into lean (LE, body condition score [BCS]: 4–5/9, n = 8) and overweight (OW, BCS: 6–7/9, n = 8) groups. Milk was collected from bitches at 5 timepoints (0.5, 1, 2, 3, and 4 weeks of lactation). Growth curves of a total of 106 puppies born alive to LE (n = 58) and OW (n = 48) mothers and exclusively nursing on the dam were analyzed until 21 days of age. Birth weight, daily body weights, average daily weight gain (ADGg), average daily percent gain (ADG%), average daily percent gain from birth (ADGB%), and total percent gain from birth (TGB%), as well as milk dry matter, crude protein, sugar, fat, ash, and calculated gross energy, were analyzed using a mixed-model analysis of variance (ANOVA); the significance level was set at a p-value of <0.05.

Puppy birth weights were unaffected by litter size and the dam BCS. Puppy growth curves and TGB% were significantly different between the two maternal groups. ADGg, ADG%, and ADGB% were significantly higher in OW dam puppies on day 2 and day 4 after birth. Puppies born heavier remained heavier, while ADG% and ADGB% were inversely related to birth weight. Litter size had no effect on these growth parameters. Swimmer puppy syndrome was observed in eight puppies from three OW dam litters. Dam BCS had no significant effect on milk macronutrients in the first 4 weeks of lactation.

In conclusion, despite the similar day-to-day neonatal body weights between the maternal groups, puppies from OW dams grew differently, gaining more weight in the first week of life. Factors other than milk macronutrient composition are likely responsible for these differences.